Furnace-grate.



W. M. DUNCAN.

FURNACE GRATE. A-PPLlcATioN FILED Diano. ma.

Patented Mar. l1, 12H9.

2 SHEETS-SHEET Y [A 'VENTUR l lll ms nomas uns w Haw-uma, wnswmcmu. n.c.

W. M. DUNCAN. FURN'ACE GRATE.

AFPLHAHON4 FI'LED 1150.10, 1918. 1529731 16. Patented Mm. 11,1919.

2 SHEETS-SHEET 2.

5 Eiga- WILLIAM M; DUNCAN', OF ALTON, ILLINOIS.

FURNACE-GRATE.

Specification ofLetters'Paten- A Patented llIlI'. 11, 1,919'. y

Application filed Decemberv 10, 1.91'8. Seria1No..266,120.

To all whom t may concern.'

Be it known that I, WILLMM'M. DUNQAN, a citizen of the United States ofAmerlca,

a resident of Alton, in the county of Madison, Statey of Illinois, haveinvented certain new and usefulf Improvements in Furnace- Grates, ofwhich the following is a full, clear, and exact description, reference.be,- ing had to the, accompanying drawings, forming a part of thisspecification.

This invention relates to improvements in furnace gratos, and moreparticularly to a chain grate adapted to form part ofV a mechanicalstoker. Grrates` of this kind usually consist ofendless rows ofgratelinks and pivot rods extending throughl the several rows to formpivotal connections for the links.

The endless rows of grate links travel slowly to receive thefuel nearone end` of the grate structure,l and to discharge the ashes at theother end. Sprocket wheels arcor-dr narily used to. transmit power totheendless rows of grate links, the links being pulled in an. endlesscourse, and the pulling stresses being transmitted through the pivotswhereby the links are connected. Each grate link is usually providedwith two pivot-receiving openings, and if all the links are made exactlyValike the pulling stresses would be uniformly distributed throughoutthe several rows ofgrate links.

However, in actual practice, the links are usually iron castings, andowing to inaccuracies in the castings the links are not exact duplicatesof each other. The distance between the pivot-receiving openings willvary, and some of these openings may be larger than others. Prior tothis invention, the rows of inaccurately formed links have beenconnected together by means of rigid pivot rods, sponse to the pullingaction of the links. As a consequence, the pulling stresses have notbeen uniformly distributed throughout the grate. Some of the links areseverely tensioned by the pulling stresses, while others are free oftension, and some portions of they rigid pivot rods are subjected tovery severe bending or shearing stresses, while other portions of therigid rods merely support the loose links. Y

The main object of the present invention is to uniformly distribute thepulling stresses throughout the grate, thereby avoiding undue stressesto which the inaccurately which do not yield in reformed structure isordinarily subjected. Instead of using rigid-pivot rods, the severalrows of grate links are flexibly connected together, preferably by meansof iiexible pivot members adapted toy yield so as to compensate forinaccuracies in the grate structure. When the rows of grate linksA arepulled and placed under tension, the flexible vpivot ymembers will bendand automatically adjust themselves to receive the` stresses transmittedthrough all of the endless rows of grate links.. Each link will thenfirmly engage two of the flexible pivot members, and the pullingstresses will ber transmitted throughout all of the endless rows oflinks and more uniformly distributed through all of the links andpivots.

I/Vhen the grate is in4 service, the endless Vchains travel aroundwheels at the ends of the structure, and to permit such movements thelinks should turn freely on the pivot members. Ashes, line particles offuel, and other matter drop onto the pivot members, and the pivots aresubjected to high temperatures. In actual practice, I have found thatsevere strains resulting in breakage are sometimes caused by the failureof the ordinary pivot rods to provide free pivotal connections. Inaccordance with the present invention, the grate links may be pivotallyconnected together by means of spiral formed flexible pivot members,preferably wire rope members. These twisted, spirally formed 'membersexert a crushing or grinding action on the material which passes intothe pivot-receiving openings, and acting like screw conveyers, they tendto feed or deflect the fine material from the openings. Therefore,spirally formed pivot members always form the desired loose, freepivotal connections for the links.

Figure I is a side elevation, partly in section, of a mechanical stokerprovided with a grate constructed in accordance with the presentinvention.

Fig. II is an enlarged transverse section on the line II-IL Fig. I,showing the upper portion of the chain grate.

Fig. III is a fragmentary section drawn to a very large scale, andshowing one of the spirally formed pivot members mounted in a gratelink.

To illustrate the invention I have shown a mechanical stoker comprisingan endless chain grate supported by a large, portable frame, said frameincluding side frame members l mounted on wheels 2, rods 3 eonnectingthe side frame members, and rollers a mounted on the rods 3.

T he endless chain grate comprises several endless rows of grate links 5connected by means of pivot members A arranged transversely of thegrate. A power shaft 7, mounted in the side frame members l, is providedwith sprocket wheels S for transmitting movement to the endless grate,each grate link 5 (Figs. Il and lll) being provided with circular bosses5 adapt-ed to-y reeeive the sprocket teeth. The chain grate is mountedon the sprocket wheels 8, and also on a plain idle wheel or roller 9,the latter being mounted on a shaft l0. The fuel passes from a. hopperl2 to the top face of the grate, and the grate links travel over therollers 4.

Each grate link 5 is preferably provided with two pivot-receivingopenings, and the flexible pivot-s A, preferably sections of wire rope,pass through said openings to pivotally connect the grate links in eachof the endless rows. Each wire rope member consists of a number ofrelatively small wires twisted to form several spirals which extendlongitudinally of the rope. These spirally formed pivot members form adesirable flexible Connection for the endless rows of grate links, andthey permit the links to turn freely in passing around the wheels 8 and9.

The ends of the pivot members project from the side faces of the gratestructure, as shown in Fig. ll. Retaining members, in the form of splitcollars 12, are preferably clamped onto the projecting ends of the pivotmembers, so as to retain the latter in the pivot-reeeiving openings.rlChe split col- Copies of this patent may be obtained for ve centseach,

lars l2 may be secured by means of clamping bolts 13, which pass throughextended portions of the collars as shown in Figs. Il and Hl.

I claim:

l. A ehain grate comprising rows of grate links having pivot-receivingopenings, and flexible pivot members passing through said openings andpivotally connecting the grate links.

2. In a chain grate, rows of grate links having pivot-receivingopenings, and flexible pivots comprising wire rope members arrangedtransversely of the rows of grate links and passing through saidopenings to pivotally connect the grate links.

3. ln a chain grate, endless rows of grate links having pivot-receivingopenings, spirally formed pivots Comprising wire rope members arrangedtransversely of the rows of grate links and passing through saidopenings to pivotally connect the grate links in each of said endlessrows, and retaining members secured to the ends of said wire ropemembers to retain said rope members in said openings.

fl. ln a chain grate, endless rows of grate links having pivot-receivingopenings, spirally formed flexible pivots comprising wire rope membersarranged transversely of the rows of grate links and passing throughsaid openings to pivotally connect the grate links in each of saidendless rows, and split collars clamped onto the ends of said wire ropemembers to retain said rope members in said openings.

In testimony that l claim the foregoing l hereunto aftix my signature.

VILLIM M. DUNCAN.

by addressing the Commissioner of Patents,

Washington, 33. C.

